In the early 2010s, it became clear that global elimination efforts for trachoma were being hampered by incomplete mapping, and thus the Global Trachoma Mapping Project (GTMP) was initiated to provide much-needed data. The scale and impact of the GTMP cannot be overestimated. Using a standardised, valid, reliable and reproducible methodology, the GTMP surveyed over 1,546 districts and examined over 2.6 million people across 29 countries in just three years, making it the largest infectious disease survey ever undertaken.
The results of the GTMP were immediately relevant for national Ministries of Health, international nongovernmental organisations and donors in their programmatic activities. Ophthalmic Epidemiology has played an important role in dissemination, and this issue (volume 25) is the last special issue devoted to the GTMP.